Avent Classic Anti-Colic Bottle has been improved to provide an even more enjoyable feeding experience. The clinically proven, anti-colic system is now integrated into the nipple, making the bottle extra easy to clean and assemble. The AirFree™ vent is designed to help your baby swallow less air. The teat stays full of milk, even when horizontal, for upright feeding. Reducing the air a baby ingests can help ease common feeding issues like colic, gas and reflux.